# superimpose a list of point pattern
# 
# Author: Guochun Shen
# Data:   2011-12-19
# Project:spatial statistic
# Email:  shenguochun@gmail.com
###############################################################################

lsuperimpose=function(data){
	re=data[[1]]
	for(i in 2:length(data)){
		if(data[[i]]$n!=0)
			re=superimpose(re,data[[i]],check=FALSE)
	}
	return(re)
}

